Mickey Mouse boots were developed for the military, I believe. They're double walled rubber boots that have an air space between the walls. Very warm, but so large they make the person's feet who's wearing them look like the feet on the Mickey Mouse cartoon character. Thus the name.
Most pack boots (leather tops, rubber bottoms) with felt liners are quite warm.
I recently picked up a pair of Muck Boots, Woody Max model, mainly for slogging through water on the way to some of my deer stands. Didn't buy them for warmth, but I've found them to be very warm, certainly up to the cold weather in Northern Wisconsin in November.